Select only good quality, plump, fresh mussels, shelled and debearded. Put the raw mussels into a strainer and drain well. Wash the lemongrass stalk, trim off the leaves and woody top portion and discard. Slice the stalks into fine rings till you have the required quantity. If possible, use only the tender lower portions of the stalk. Peel the shallots, and also slice fine. Wash the mint leaves, and use the leaves whole. Wash the hot fresh Thai chili peppers (substitute milder chili if desired), and lightly crush with a heavy object or the flat of a knife. Bring a pot of water to a boil and blanch the mussels, using the strainer, quickly in the boiling water. Put the mussels into a bowl, let cool then add lime/lemon juice and fish sauce and mix well. Add the sliced lemongrass, sliced shallots, crushed chili peppers, mixed together. Add mint leaves, and lightly toss together. Serve on a platter lined with leaves from the lettuce, and garnish with some extra mint leaves and slices of the mild red chili pepper. Serve the remaining lettuce leaves on the side as an accompaniment. Translated by Padej Gajajiva from "Homemaker Book 5 cm by Ponsee Gajajiva.